In order to eliminate the sensitivity to field noise and microphonics of a vibrating sample magnetometer it is sufficient to add trimming coils which are adjusted to produce no signal when the applied field is deliberately driven at the frequency ω0 which is to be used for vibrating the sample. A mechanical chopper which discriminates against all even harmonics and against third harmonics is discussed. The use of eddy currents to precisely align a sample in a null measurement of magnetization is described.
展开▼
